Methane (CH4), the simplest aliphatic hydrocarbon, can be measured using infra-red absorption or the flame ionisation detector principle.
Infra-red is a widely used method with the major limitation for methane being a cross sensitivity to other hydrocarbon species. Infra-red is most appropriate for measuring methane at percentage levels in applications such as landfill or bioscience.
Flame ionisation is a non-selective technique for measuring total hydrocarbons. It can be used for methane where no other hydrocarbons are present or in conjunction with a specially designed catalyst used to oxidise non-methane hydrocarbons species contained in the sample.